She was so excited by the shrinkage that she now wanted to try out the opposite, grow. Under great exertion she managed to pick the growth vial and when she was ready to drink it a Butterfly suddenly flew in through an open window! It landed on the table and having mistaken the growth vial for delicious nectar it eagerly drank all of the contents of the vial. Mary was shocked when she saw that and soon the butterfly began to grow. And grow. And grow. Soon it would become even bigger than a human! Mary had to do something...
She went into the kitchen to get a knife but the way to it was already very hard and long, being so small. When she finally arrived the butterfly was already human sized and still growing! It was very hard for her to hold the knife but under great exertion she managed to do it. She went back into the living room as fast as she could and managed to hit the butterfly! She was stabbing it so often until she could be certain that its dead.
She was very disturbed by what she just had done but she had no other choice. It was either her or him. Now she just had to grow back and clean this mess up. But when she wanted to refill the growth vial it didnt work! She immediatly thought that it must be impossible to refill a vial when its contents are completely used up, like the butterfly did. So she had to find another way to grow back.... and she already had an idea!
That growth serum must be still in the butterflys blood, so if she drinks its blood, she can grow back to her old size! But to do that.... well.... drinking bug blood isnt easy.